look at the manufacturer of your computer's video hardware, (or video card) go to the manufacturer's website, and look up the product by the model number. You should find the drivers and updates posted where you can download them.
turn off the antivirus, install the software or updates, restart the computer and turn the antivirus back on.
Many manufacturers require that you delete the current drivers before installing the new ones.
Now, when you first uninstall a driver and restart the computer, a microsoft wizard will pop up to install the driver, ignore that and cancel it.
Instead, install the driver you downloaded from the manufacturer, without using the pop up install wizard.
Now, to delete a driver before installing a new one, click my computer, click control panel, click add remove programs, look on the list. Find the driver you want to uninstall, and click delete.